Convergence Challenges
Protecting critical infrastructure involves bridging the gap between Information Technology (IT) and Operational Technology (OT). This convergence presents unique challenges. OT environments are often characterized by legacy protocols that lack modern security features, flat trust zones where any device can communicate with another, and extremely limited windows for patching due to operational uptime requirements. Furthermore, these systems typically provide minimal native telemetry, making it difficult to detect sophisticated threats. Our [OT Infrastructure Security Case Study](/resources/case-studies/ot-infrastructure-security) details our approach.
Segmentation Strategy
A robust segmentation strategy is the foundation of OT security. This involves defining network zones based on process criticality, grouping similar systems together. Access between these zones must be strictly brokered through identity-aware gateways that enforce protocol-specific allowlists, ensuring that only expected and authorized communication can occur. This "zero-trust" approach for OT networks is critical for preventing an adversary from moving laterally from a less-critical system to a highly sensitive one. This is also crucial for [Medical Device Security](/resources/blog/medical-device-security).
Telemetry Augmentation
Given the lack of native telemetry in many OT systems, security teams must augment their visibility with specialized tools. Passive network analysis, which monitors traffic without interacting with the OT devices themselves, is essential for understanding normal communication patterns. This can be supplemented with tuned canary assets—decoy systems designed to attract and detect attackers—and OT-specific anomaly baselines that can identify subtle deviations from normal operational behavior, providing an early warning of a potential incident.
Response & Recovery
In an OT environment, response and recovery procedures must be carefully planned to ensure patient safety and operational continuity. This includes creating isolated runbooks for each zone, detailing the specific steps to contain an incident within that segment. It is also critical to pre-stage a manual override decision matrix. This matrix should be developed in collaboration with engineering and operations teams to define the exact conditions under which a safety-critical process can be manually overridden, ensuring that security responses do not inadvertently create a more dangerous situation.
Metrics
To measure the effectiveness of the OT security program, track metrics that reflect real-world risk reduction. Key indicators include the dwell time for lateral movement (how long an attacker can move undetected within the network), the number of unauthorized protocol attempts blocked by segmentation gateways, the duration of zone isolation drills (a measure of response readiness), and the percentage of high-criticality assets covered by the inventory. These metrics provide a clear picture of the program's maturity and its ability to protect critical operations.
Sources & Further Reading
NIST SP 800-82 Rev.3 (ICS security).
ISA/IEC 62443 Series.
CISA Shields Up & OT Advisories.
MITRE ATT&CK for ICS.
NERC CIP Standards (energy sector).
ENISA Threat Landscape for ICS/OT.
Key Takeaways
Hybrid visibility & engineered friction reduce propagation risk without halting operations.
Recommended Reading
7 Common Zero Trust Misconceptions (and What Actually Matters)
Zero Trust is not a product, vendor SKU, or a single architecture pattern—here is what actually produces risk compression.
Detection Engineering Playbook: Hypothesis → Validation → Automation
Move from ad-hoc rule writing to a measurable hypothesis-driven detection pipeline.
Mapping MITRE ATT&CK to Detection Engineering Sprints
Turning ATT&CK from a static coverage spreadsheet into a living detection hypothesis engine.
Purple Teaming Framework: Continuous Collaborative Detection Uplift
Continuous purple teaming converts offensive insights into validated detection and response improvements.
Medical Device Security: Lifecycle Hardening & Clinical Safety Alignment
Lifecycle hardening and monitoring patterns for connected clinical & IoT medical devices.